A diagonal line across 16 MHz, and a shorter, repeating pattern, repeating 4 times a second.

Notices where this attachment appears

1. Embed this notice
   blinry (blinry@chaos.social)'s status on Monday, 11-Mar-2024 05:22:44 JST blinry

   in reply to

   25 & 26: See ionosondes and radar signals

   In the low frequencies, occasionally, you can hear a short *chirp*! :D These are caused by ionosondes, scientific instruments which measure the properties of the ionosphere by sweeping a wide frequency spectrum.

   Another signal (which I accidentally got in the same screenshot) is a radar system – in this case, according to the Signal Identification Wiki, it's a "CODAR" system, used to measure the motion of water waves and currents along coasts! :O